It's easy to make a coloured block of text, or a simple diagram (e.g. a flag), but to make it look like it's actually real, you'll need to follow the steps in this tutorial.
This is an advanced Photoshop tutorial, which will show you how to create a plastic texture on text, buttons or icons, using a combination of lighting effects, and the Screen blending mode.
Use Color Dodge to brighten your graphics.
Photoshop has many different ways of blending layers. Different blending modes determine how the pixels on one layer effect the pixels on other layers beneath it.